In recent years, there has been widely used non-contact IC tag which is fitted to to-be-controlled persons or goods (adherends) for control of circulation, etc. of such persons or goods. This IC tag can memorize and store data in an IC chip built therein. Further, since the IC tag can communicate in non-contact with a interrogator via a radio wave, the data memorized in the IC chip can be exchanged with the interrogator.
As the application fields of IC tag, there are various fields, for example, its use being inside of communication ticket for control of section of riding or fare, control of coming and goings of peoples in business, etc., stock control of goods, control of physical distribution, etc. IC tags of various forms are being produced so as to match such application fields.
Throw-away IC tag is fitted to, for example, a commodity and is placed at a shop together with the commodity; when the commodity has been sold, the data memorized in the IC chip is read by a interrogator. Thereby, the role of the IC tag is over.
In the throw-away IC tag whose role has been over, the data memorized in the IC chip remains still. Therefore, the control manage of the data memorized in the IC chip of used IC tag is important. As an example of improper use of the data memorized in the used IC tag, there is a case that the IC tag (which was fitted to a commodity and used properly) is peeled from the commodity, the data memorized in the IC chip is read, and this data is used illegally. It is also considered that the memorized data of the discarded IC tag is falsified for illegal use.
In order to prevent such illegal use, it is preferred to deactivate the function of used IC tag. As the deactivation method, there is proposed a method of cutting the electronic circuit contained in an IC tag, with scissors or the like (JP 2002-366916A, paragraph No. 0033). In this proposal, however, a labor of cutting an electronic circuit is needed for deactivation, which does not match a requirement for automation.
There is also a proposal of forming in advance, in the substrate of IC tag, portions of different peeling strengths so that, when the IC tag is peeled from a commodity and recovered, the electronic circuit of the IC tag can be destroyed (JP 2000-57292A, claim 1). In this proposal, since the destruction of electronic circuit takes place owing to the difference in peeling strength, stable control of peeling strength is important. Further, there is required a step for forming a peeling layer having different peeling strengths, increasing the number of steps for IC tag production.